Utilização de betaína em substituição parcial de diferentes fontes de metionina na dieta de frangos de corte

Abstract

Betaine has been used as a source of sparing methionine in the diet of broilers, once its cheaper than methionine, which reduces the final cost of diet. Another factor of interest in the use of betaine is over its osmo-protector function, that assists in the regulation of cell function, especially in stress phases. In this study two sources of methionine (DL-Methionine and Methionine-MHA) were studied at different levels of methionine + cystine, and two inclusion percentage of betaine in the diet at different raising stages. From 1 to 7 and 8 to 21 days, the birds fed diets with reduced levels of methionine and cystine without betaine supplementation underperformed. When deficient diets were supplemented performance equated to the positive treatments. There was no difference as to sources of methionine. In the 22-42 days period, dry matter of carcass and carcass yield, breast, leg, wing and abdominal fat did not differ. Methionine sources differed significantly for feed intake, protein deposition rate and relative weight of liver. Weight gain showed satisfactory result considering the use of betaine, and the 7% reduction with supplementation showed equal performance to the control. When DL-Methionine was used, higher protein deposition rates were observed with 7% reduction in the amount of methionine + cystine supplementation with 500 g ton-1 Betaine. For Methionine-MHA the same was observed with 7% reduction methionine + cystine and supplementation of 1000 g ton-1. The fat deposition rate was statistically higher in treatments supplemented with betaine, but abdominal fat did not differ.